Question

suggest a quantitaive method for estimation of gas whcih protect as from uv rays

Answer 1

The gas which prevents us from uv rays is ozone.It is estimated quantitatively by using potassium iodide solution.Ozone gas is bubbled through potassium iodide solution.Iodine is liberated by the reaction between potassium iodide and ozone gas.The liberated iodine gas is estimated by titration with sodiumthiosulphate.Thus, by knowing the amount of iodine gas liberated, the amount of ozone gas absorbed by the solution can be known quantitatively. The reactions are as follows:

$O_3+2KI+H_{2}O\to I_2+2O{H}^{-}+O_2$
Ozone Iodine
$$\begin{gathered} I_2+2N{a}_2{S}_2{O}_3\to N{a}_2{S}_4{O}_6+2NaI \\ Sodium \\ thiosulphate \end{gathered}$$